Progressive parameter scan for cochlear implants

Abstract

A channel fitting process is described for a cochlear implant. A check is made for a channel fitting response condition to a stimulation signal, and if the condition is present, a channel operating parameter is set for the current electrode contact based on the channel fitting response condition, and if channel operating parameters have been set for all the electrode contacts, the channel fitting process ends. Otherwise, a next electrode contact is selected, the stimulation level is changed by a channel fitting increment, and if a stimulation level limit has been reached, the channel fitting process ends, or otherwise, the currently selected electrode contact is stimulated with the stimulation signal at the current stimulation level and the channel fitting process repeats.

What is claimed is: 
     
       1. A method for determining cochlear implant operating parameters for a plurality of electrode contacts in an implantable electrode array, the method comprising:
 stimulating a first electrode contact with an initial stimulation signal at an initial stimulation level; and 
 performing a channel fitting process including:
 checking for a channel fitting response condition to the stimulation signal; 
 when the channel fitting response condition is present:
 i. setting a channel operating parameter for the selected electrode contact based on the channel fitting response condition and completing the channel fitting process for the selected electrode contact, and 
 ii. if channel operating parameters have been set for all electrode contacts, ending the channel fitting process; 
 
 and when the channel fitting response condition is not present or when channel operating parameters have not been set for all electrode contacts:
 iii. selecting a next electrode contact, 
 iv. changing the stimulation level by a channel fitting increment, 
 v. if a stimulation level limit has been reached, ending the channel fitting process, 
 vi. otherwise, stimulating the selected electrode contact with the stimulation signal at the current stimulation level and repeating the channel fitting process. 
 
 
 
     
     
       2. A method according to  claim 1 , wherein before setting the channel operating parameter for the selected electrode contact, a refine measurement process is performed including:
 stimulating the selected electrode contact with a stimulation signal at a stimulation level at which the current electrode contact was last stimulated where no channel fitting response condition was present; and 
 checking for a refine measurement response condition to the stimulation signal if the refine measurement response condition is present, ending the refine measurement process, and otherwise:
 i. changing the stimulation level a refine measurement increment less than or equal to the channel fitting increment, 
 ii. if the stimulation level limit has been reached, ending the refine measurement process, 
 iii. otherwise, stimulating the current electrode contact with the stimulation signal at the current stimulation level and repeating the refine measurement process. 
 
 
     
     
       3. A method according to  claim 2 , wherein the refine measurement increment is a level increase. 
     
     
       4. A method according to  claim 2 , wherein the refine measurement increment is a level decrease. 
     
     
       5. A method according to  claim 2 , wherein the refine measurement response condition and the channel fitting response condition are the same. 
     
     
       6. A method according to  claim 2 , wherein the refine measurement response condition and the channel fitting response condition are different. 
     
     
       7. A method according to  claim 1 , wherein performing the channel fitting process includes ending the process if the stimulation level reaches an uncomfortable loudness (UCL). 
     
     
       8. A method according to  claim 1 , wherein the stimulation level limit is a standard start value when the channel fitting process begins, and then reflects the channel operating parameters as they are set. 
     
     
       9. A method according to  claim 1 , wherein the channel fitting increment is a level increase. 
     
     
       10. A method according to  claim 1 , wherein the channel fitting increment is a level decrease. 
     
     
       11. A method according to  claim 1 , wherein the channel operating parameter includes a most comfortable loudness (MCL) stimulation level. 
     
     
       12. A method according to  claim 1 , wherein the channel operating parameter includes a threshold (THR) stimulation level. 
     
     
       13. A method according to  claim 1 , wherein the channel fitting response condition includes presence of an electrically evoked compound action potential (ECAP). 
     
     
       14. A method according to  claim 1 , wherein the channel fitting response condition includes presence of an electrical stapedius reflex threshold (ESRT). 
     
     
       15. A method according to  claim 1 , wherein the channel fitting response condition includes presence of an electrically evoked auditory brain stem response (EABR). 
     
     
       16. A cochlear implant system fit to an implanted patient using the method according to any of  claims 1 - 15 .